1. Field of the Invention
The present invention relates to a method of producing a composition, which is suitable for producing a composition by melt-kneading a thermoplastic resin and a rubber in an extruder, and an extruding equipment.
2. Description of the Related Art
As a composition prepared by compounding a rubber with a thermoplastic resin, for example, a polypropylene composition having an improved impact resistance, which is produced by compounding and melt-kneading polypropylene with a small amount of an ethylene-propylene copolymer rubber, a polystyrene-based composition having an improved impact resistance, which is produced by melt-kneading a polystyrene with mixing a small amount of butadiene rubber, and a polyphenylene ether-based composition having excellent moldability and impact resistance, which is produced by melt-kneading polyphenylene ether and a styrene-butadiene rubber.
Melt-kneading of thermoplastic resin and rubber has been generally conducted by mixing a thermoplastic resin with a rubber and feeding the mixture in a single screw extruder or a twin-screw extruder. The thermoplastic resin is generally used in the form of pellets or powders, while the rubber is used in the form of pellets or finely cut pieces.
In case where a powdered thermoplastic resin and a rubber in the form of pellets or cut pieces are mixed and charged in an extruder, the thermoplastic resin and rubber are not melt-kneaded uniformly in the extruder, thereby causing a problem such as deviation in component ratio of the resulting composition.